The present invention relates to disk drive suspension assemblies, and especially relates to liquid crystal polymer disk drive suspension assemblies and load beams therefor.
Disk drive suspension assemblies provide flexible support for electronic devices in order to support an electrical connection between a magnetic head and disk drive such as those used in computer equipment. Essentially, the suspension assembly is a very precise metal spring with connecting circuitry that holds recording heads at microscopic distances away from a disk in a rotatable storage device, i.e. a disk drive. The suspension is critical to the operation of the device. The assembly, which has been increasingly important in attaining better device performance, including greater data storage capacity, faster access to data, and increasing reliability, enables the magnetic head to be located close to the device without damaging the head as a result of contact with the rotating device.
One conventional disk drive suspension assembly includes a stainless steel foil member for providing spring action, a layer of polymeric, dielectric material (typically polyimide) thereon with the appropriate circuit pads and circuit lines located on the polymeric material.
U.S. Pat. No. 5,145,553 to Albrechta et al. discloses a disk drive suspension assembly having a stainless steel base member, a dielectric layer (polyimide) on the base member and a conductive circuit (copper) on the dielectric layer. The copper-containing circuitry and stainless steel base member are simultaneously etched using a cupric chloride etchant solution to effectively remove desired portions of these metallic materials and produce the desired flexible circuit member. Although this disk drive suspension assembly is particularly usefull in the computer industry, its sensitivity to atmospheric changes, such as temperature and relative humidity (hygrothermal conditions) reduces computer tolerances, thereby limiting its usefulness under varying conditions. What is needed in the art is an improved rotatable data storage suspension assembly and a load beam that is readily produced and possesses improved hygrothermal properties, and electrical performance.
Recent advances in disk drive technology have led to changes in the construction of suspension assemblies, resulting in more complex suspension assemblies. Such suspension assemblies typically comprise a front portion and a rear portion, usually referred to as a mount plate. The front portion usually comprises a circuit element and a load beam. The front portion may be conceptually divided into two parts, a flexible hinge portion and a slider support portion. The flexible hinge portion is generally attached to one end of the rear portion. The other end of the rear portion has means for pivotally mounting the suspension assembly to the disk drive frame
The circuit element connects the read/write head to the read/write control circuit. The load beam provides the major structural support for the suspension assembly and must do so while also providing localized flexibility. As data tracks become narrower and closer together, the load beam materials need the capability to be locally tailored (typically by selectively removing material) to provide the varying amounts of bend and stiffness required at different locations along the load beam. This selective removal is done either by industry standard processes such as chemical etching or plasma depending upon materials involved. Furthermore the load beam needs excellent hygrothermal stability properties so as to perform consistently regardless of environmental conditions. As current load beams are typically either just stainless steel or a polymer sandwiched between two stainless steel layers, it is has been difficult to modify current load beams to meet these requirements. Accordingly there remains a need in the for materials for use as load beams that that can be adjusted to provide characteristics such as localized bend and flex, as well as improved hygrothermal properties.
The present invention relates to a liquid crystal polymer disk drive suspension assembly and a method for making the same. The assembly comprises: a support; an electrically conductive layer; and a dielectric liquid crystal polymer material disposed between, in intimate contact with, and adhered to the support and the conductive layer.
The method for making the suspension assembly of the present invention comprises: forming a dielectric liquid crystal polymer film; disposing said liquid crystal polymer film between a support and an electrically conductive layer; and bonding the liquid crystal polymer layer to the electrically conductive layer and said support.
In another embodiment, a suspension assembly comprises a mount plate having a load beam mounted thereon, and a circuit element disposed on a load beam, wherein the load beam comprises a liquid crystal polymer layer disposed between and in intimate contact with a first metal layer and a second metal layer. Such load beams may be tailored to provide localized blend and flex, and have excellent hygrothermal properties.
These and other objects, features and advantages of the present invention will be apparent from the following brief description of the drawings, detailed description, appended claims, and drawings.